SYNTAX

   C Syntax
          #include <mpi.h>
          #include <mpi-ext.h>

          int MPIX_Comm_is_revoked(MPI_Comm comm, int *flag)

   Fortran Syntax
          USE MPI
          USE MPI_EXT
          ! or the older form: INCLUDE 'mpif.h'

          MPIX_COMM_IS_REVOKED(COMM, FLAG, IERROR)
               INTEGER COMM, IERROR
               LOGICAL FLAG

   Fortran 2008 Syntax
          USE mpi_f08
          USE mpi_ext_f08

          MPIX_Comm_is_revoked(comm, flag, ierror)
               TYPE(MPI_Comm), INTENT(IN) :: comm
               LOGICAL, INTENT(OUT) :: flag
               INTEGER, OPTIONAL, INTENT(OUT) :: ierror

INPUT PARAMETERS

       • comm: Communicator (handle).

OUTPUT PARAMETERS

       • flag: true if the communicator is revoked.

       • ierror: Fortran only: Error status (integer).

DESCRIPTION

       Returns  flag  =  true  if  the  communicator  associated  with the handle comm is revoked at the calling
       process. It returns flag = false otherwise. The operation is local.

HOW CAN A COMMUNICATOR BECOME REVOKED

       A communicator can become revoked when

       1. the user calls the MPIX_Comm_revoke procedure on comm to revoke the communicator at the local process;

       2. an MPI  operation  raised  the  error  class  MPIX_ERR_REVOKED  because  another  process  called  the
          MPIX_Comm_revoke procedure on comm;

       3. the  communicator has the info key mpi_error_range set to group or universe, in which case the failure
          of any process in, respectively, the group of comm or the MPI universe caused an operation to raise an
          error of class MPIX_ERR_REVOKED.

REVOKE PROPAGATION AND ORDERING

       Note that in a multithreaded application, a thread calling MPIX_Comm_is_revoked may return  flag  =  true
       before  the  operation  that  raises  the  first  exception  of class MPIX_ERR_REVOKED has completed in a
       concurrent thread.

EFFECT OF A COMMUNICATOR REVOCATION

       Once a communicator has been revoked at an MPI process,  all  subsequent  non-local  operations  on  that
       communicator  (with  some  exceptions listed below), are considered local and must complete by raising an
       error of class MPIX_ERR_REVOKED at that MPI process.

OPERATIONS ON A REVOKED COMMUNICATOR

       The following operations never raise an error of class MPIX_ERR_REVOKED, and complete with  their  normal
       semantics on a revoked communicator.

       • MPIX_Comm_agree

       • MPIX_Comm_iagree

       • MPIX_Comm_shrink

       • MPIX_Comm_ishrink

ERRORS

       Almost  all  MPI  routines  return  an  error  value; C routines as the return result of the function and
       Fortran routines in the last argument.

       Before the error value is returned, the current MPI  error  handler  associated  with  the  communication
       object  (e.g.,  communicator, window, file) is called.  If no communication object is associated with the
       MPI call, then the call is considered attached to MPI_COMM_SELF and will call the  associated  MPI  error
       handler.   When   MPI_COMM_SELF   is   not  initialized  (i.e.,  before  MPI_Init/MPI_Init_thread,  after
       MPI_Finalize, or when using the Sessions Model exclusively) the error raises the initial  error  handler.
       The  initial  error handler can be changed by calling MPI_Comm_set_errhandler on MPI_COMM_SELF when using
       the World model, or the mpi_initial_errhandler CLI argument to mpiexec or info  key  to  MPI_Comm_spawn/‐
       MPI_Comm_spawn_multiple.   If no other appropriate error handler has been set, then the MPI_ERRORS_RETURN
       error handler is called for MPI I/O functions and the MPI_ERRORS_ABORT error handler is  called  for  all
       other MPI functions.

       Open MPI includes three predefined error handlers that can be used:

       • MPI_ERRORS_ARE_FATAL Causes the program to abort all connected MPI processes.

       • MPI_ERRORS_ABORT An error handler that can be invoked on a communicator, window, file, or session. When
         called  on  a  communicator,  it  acts  as if MPI_Abort was called on that communicator. If called on a
         window or file, acts as if MPI_Abort was called on a communicator containing the group of processes  in
         the corresponding window or file. If called on a session, aborts only the local process.

       • MPI_ERRORS_RETURN Returns an error code to the application.

       MPI applications can also implement their own error handlers by calling:

       • MPI_Comm_create_errhandler then MPI_Comm_set_errhandler

       • MPI_File_create_errhandler then MPI_File_set_errhandler

       • MPI_Session_create_errhandler then MPI_Session_set_errhandler or at MPI_Session_init

       • MPI_Win_create_errhandler then MPI_Win_set_errhandler

       Note that MPI does not guarantee that an MPI program can continue past an error.

       See the MPI man page for a full list of MPI error codes.

       See the Error Handling section of the MPI-3.1 standard for more information.

       SEE ALSO:

          • MPIX_Comm_revoke

          • MPIX_Comm_agree

          • MPIX_Comm_shrink

COPYRIGHT

       2003-2025, The Open MPI Community

                                                  Sep 06, 2025                           MPIX_COMM_IS_REVOKED(3)